Hello! I've noticed on multiple occasions that using Guix on traditional spinning drives can be quite slow.
On my home machine, will is still relying on 2 x 1 TB spinning drives in RAID1, rebuilding my user profile, which contains 182 entries, takes on average about 20 minutes, even when there are no packages to be built: --8<---------------cut here---------------start------------->8--- $ time guix package -i perl --max-jobs=1 The following package will be upgraded: perl (dependencies or package changed) The following derivation will be built: /gnu/store/lhywla1z2zcz16df4hbvvvngr9zmswr7-profile.drv building CA certificate bundle... building fonts directory... generating GLib schema cache... creating GTK+ icon theme cache... building cache files for GTK+ input methods... building directory of Info manuals... building database for manual pages... building XDG desktop file cache... building XDG MIME database... building profile with 182 packages... real 19m0.126s user 0m5.648s sys 0m0.333s --8<---------------cut here---------------end--------------->8--- Most of the time remains spent after the message 'building profile with 182 package...'. That part seems IO-bound, with the spinning disks grinding heavily and the CPU mostly idling. The rest of the time (3 minutes), was used by the profile hooks. The same operation on a second, more modern machine equipped with M2 SSDs does much better and takes about 1 minute to accomplish the same, so it seems the bad performance can be mostly attributed to the much slower disk seek times of the spinning disks. On the older machine, two profile hooks are also sticking out w.r.t. the time they take (they take more than one minute opposed to a few seconds): --8<---------------cut here---------------start------------->8--- The following profile hook will be built: /gnu/store/08fanpydi7z4i3qnlqbr8iz23zdgsamw-manual-database.drv building database for manual pages... Creating manual page database... [2139/2139] building list of man-db entries... 175322 entries processed in 95.1 s successfully built /gnu/store/08fanpydi7z4i3qnlqbr8iz23zdgsamw-manual-database.drv successfully built /gnu/store/08fanpydi7z4i3qnlqbr8iz23zdgsamw-manual-database.drv /gnu/store/wzp4mk2r7r4ysciw74gqbfkyai0zmrcc-manual-database real 1m36.378s user 0m1.674s sys 0m0.108s The following profile hook will be built: /gnu/store/cir84qj587i6is4akgqand7ahg9bj938-xdg-mime-database.drv building XDG MIME database... successfully built /gnu/store/cir84qj587i6is4akgqand7ahg9bj938-xdg-mime-database.drv successfully built /gnu/store/cir84qj587i6is4akgqand7ahg9bj938-xdg-mime-database.drv /gnu/store/j0bznlj2ibnhirijhnwpkkxzz4qfk8wb-xdg-mime-database real 1m7.344s user 0m1.331s sys 0m0.053s --8<---------------cut here---------------end--------------->8--- So we should profile what's going on while generating the profile (no pun intended) and try to improve this at first since this is where most of the time is spent on spinning drives (17 minutes out of the 20 in the above example). After that we could look into the two above profile hooks. Thanks, Maxim
